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Message-ID: <0f80d7ef92366fde06f3b24fe060066e01933980.camel@hadess.net>
Subject: Re: Autopairing
From:   Bastien Nocera <hadess@hadess.net>
To:     Mihai Emilian <be.mihai22@gmail.com>,
        linux-bluetooth@vger.kernel.org
Date:   Thu, 04 Mar 2021 11:55:40 +0100
In-Reply-To: <CAP_L5iPNbYrni-U_EH=Yf5Tb3b7tGN6wFKp-h+HNE8ob028k5w@mail.gmail.com>
References: <CAP_L5iPNbYrni-U_EH=Yf5Tb3b7tGN6wFKp-h+HNE8ob028k5w@mail.gmail.com>
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On Tue, 2021-03-02 at 18:07 +0100, Mihai Emilian wrote:
> Dear bluetooth community,
> 
> I am trying to create a pairing agent using bluez API in C.
> 
> The problem that I am trying to solve is autopairing from a known list
> of MAC addresses (i.e auto-accept pairing for known devices in the
> list).
> 
> I tried registering a bluetooth agent with NoInputNoOutput capability.
> However, when I try to access Pair, I receive Authentication Failed
> error.
> 
> Another problem here is that even if I call RequestDefaultAgent after
> registration, it seems that the bluetooth settings agent (UI) is still
> called and prompts me to yes/no.
> 
> I have the following questions:
> 
> From the api doc:
> "Special permission might be required to become the default agent"
> 
> - Is there anything else I have to do to acquire these permissions?
> - The return value from RequestDefaultAgent and RegisterAgent is void.
> How can I check whether my agent has been registered/became default?
> - I also tried trusting the discovered device after registering the
> agent and trying to make it default, which didn't make any difference
> - is this required?

You might want to look at ready made pairing tools, such as bt-agent in
bluez-tools:
https://github.com/khvzak/bluez-tools

This is an example of using static pincode with unattended pairing:
https://github.com/hadess/CHIP-bluetooth-speaker/blob/master/setup.sh#L73

The bt-agent pin code file can accommodate using bluetooth addresses,
so something like:
AA:BB:CC:DD:EE:FF *
in the pin code file should work.

Cheers

> 
> Here's my source code:
> https://pastebin.com/Wj3rdHy3
> 
> Thank you for your time.
> 
> Best regards,
> Mihai